Interventional procedures can be a less invasive alternative to open surgeries for a growing number of applications. In an interventional procedure, a physician can insert a catheter or other implement into a patient through a relatively small incision and perform the procedure, whether it is insertion of a stent, removal of a malignant tissue, or any other manipulation, under image guidance. One type of image guidance is fluoroscopy, wherein real-time X-ray images are obtained by an X-ray tube and fluorescent screen or spatially resolved detector positioned on opposite sides of a patient. However, the dose of ionizing radiation delivered to patients during a fluoroscopy guided procedure, or other X-ray intensive imaging procedures, being somewhat of a concern, methods and apparatuses for dose-reduction have been developed.
A method and apparatus for adaptive exposure in X-ray imaging systems enable a surgeon to select a “region of interest” (ROI) within the available field of view of the X-ray imaging system, which can be imaged at a higher quality than the rest of the field of view. Adaptive exposure may be implemented in inverse geometry X-ray imaging systems wherein a plurality of discrete source locations, e.g. a scanning beam source or an array of discrete emitters, illuminate a spatially resolved detector in rapid sequence. The ROI may be exposed to a higher amount of X-ray flux to improve image contrast and quality relative to areas outside the ROI, so that these areas receive only the minimum amount of radiation necessary for the physician's analysis. ROI selection may be completed using a stylus or finger on a screen or otherwise tracing out an ROI on the presented X-ray image.
However, an operating room may be held to a high degree of sterility, requiring all objects to meet certain standards; a surgeon may be unable to touch a stylus or screen after beginning a procedure if the stylus or screen is not sterilized. What is needed is a method and apparatus by which a physician may control the ROI being implemented by an imaging system or other equipment parameters without risk of contamination or time-expensive processes during an interventional or other operating-room procedure. Embodiments of the present invention utilize an alternative means of human-computer interaction to offer a contact-free method and apparatus for ROI definition and related commands in an operating room.